The purpose of this study is to assess the extent to which cognitive impairment and/or depression are precipitated or exacerbated by surgery in the elderly. Specifically, the research aims include: 1) To assess the prevalence of peri-operative cognitive impairment and depression in elderly subjects; 2) To assess whether hospitalization and surgery serve as precipitating factors for cognitive impairment and depression in the elderly; 3) To define cognitive impairment in the peri-operative period as to its clinical correlates and time course; 4) To estimate the extent to which elective surgery affects recovery of pre-morbid functioning. Subjects will include patients, over 60 years of age, who are undergoing cataract or prostate surgery (150 subjects in each group) at Georgetown University Hospital. Subjects will be assessed pre-operatively, and at 7 days, 6 weeks, 3 months, 6 months, and 1 year post-operatively using the Mini Mental State Exam for cognitive screening, the Geriatric Depression Scale for evaluating depressive symptoms, and questionnaires for gathering historical and demographic information. A clinical interview and medical/neurological work-up will be performed to evaluate for a definitive diagnosis in those subjects who screen positively on prior testing. Outpatient control subjects will be similarly evaluated. This study will yield results which will confirm or dispel anecdotal reports that some elderly patients undergoing surgery deteriorate mentally after the procedure. It will identify which subjects are the most vulnerable and which circumstances the most noxious. This information will assist physicians, families, and patients in assessing the risks of surgery, and also set the stage for possible interventions which might prevent or limit untoward effects of necessary procedures. This study will lead to future research, based on the clinical correlates elucidated here, focusing on etiological and risk factors for mental status change in the surgical experience.